Digital PSAT Math Practice Question 34: Answer and Explanation

Question: 34

What are the two solutions for x in the equation 4x² + 8x - 4 = 0?

• A.
• B.
• C.
• D.

Correct Answer: D

Explanation:

(D) Solve by simplifying and completing the square:

Then complete the square by adding 1 to both sides:

Then factor the left-hand side:

Then take the square root of both sides, remembering to include both the positive and the negative values on the right:

Solve for x to find the solutions:

Alternatively, you could solve this using the quadratic equation. Start by dividing by 4 to simplify:

This is equivalent to the answers x = - 1 and x = - - 1.